Management of Commercially Generated Radioactive Waste - U.S. ...

6.11
bridge crane would remove the loaded shipping cask and move it to the confinement section of
the building. The lid would be removed and the cask aligned with a hot cell port. The HLW
or spent fuel canisters would be removed remotely to a storage rack within the hot cell.
An interim dry storage area adjacent to the hot cell would have space for a 1-month sup-
ply of canisters.
The hot cell would include space for checking the canisters for visible damage, radia-
tion leakage, and surface temperature. Facilities would be provided to decontaminate waste
handling equipment in case of a canister failure. Damaged canisters would be overpacked and
returned to the processing and emplacement facility for repacking.
The receiving facility would also provide auxiliary services such as ventilation, equip-
ment maintenance, and a control system.
Canister Transporters. Canister transporters, similar to those used for subsurface
transportation and emplacement in the mined geologic repository (Section 5.4), would be used
to transfer the waste from the receiving facility to the emplacement facilities. Each trans-
porter would consist of a wheeled vehicle suitable for operation on site roadways, a shielded
transfer cask, and equipment for raising and lowering canisters in and out of the transfer
cask. In the receiving facility, the transporters would be positioned over a portion of the
hot cell to bottom load the canisters into the transfer cask. At the emplacement facility,
the transporters would be positioned over the temporary storage area and the canisters would
be bottom discharged into temporary storage.
Drilling System. The drilling rigs would be similar to those used in the gas and petro-
leum industries and would be portable for movement from one hole location to another on the
site. Each complete rig would require a clear, relatively flat area, approximately 120 x 120
m (400 x 400 ft), at each hole location (McClean 1977).
In the reference concept, the drilled hole for spent fuel is 48 cm (19 in.) in diameter
and 10,000 m deep (Bechtel 1979a). For HLW, the hole is 40 cm (16 in.) in diameter. The
depth and diameter, however, could vary depending on the geologic medium, the depth required
to satisfy containment requirements, and the drill rig capacity. For HLW, the hole would be
fully cased to the required depth with seamless steel pipe about 40 cm in outside diameter,
which would reduce the hole diameter available for waste.
Oil field rotary drilling techniques would be used to sink the holes, which may be step-
ped down in diameter as the depth increases. To seal the pipe to the rock, a grout would be
forced through the pipe and then back up between the wall of the hole and the outside of the
casing. The bottom of the hole would be sealed.
During the drilling and emplacement operation, the hole would be kept full of drilling
mud to facilitate drilling, prevent casing and canister corrosion, minimize casings sticking
to the sides of the hole during installation, and counter lithostatic pressure.
Emplacement Facilities. Each emplacement facility would include a confinement enclosure
to provide a controlled environment for emplacement operations, and the temporary canister